WiFi is a set of wireless network protocols based on IEEE 802.11 standards. These protocols are used to allow nearby devices to share data via radio waves and local area networking. These networks are used worldwide in small and large offices to connect desktop computers and tablets, laptops, smart TVs, printers and smart speakers to one another and to a wireless router for Internet access. Wireless access points can also be used in public places such as coffee shops, libraries, airports and hotels to provide public Internet access for mobile devices.
Wi-Fi trademark is owned by the Wi-Fi Alliance. This non-profit organization restricts the usage of the term Wi-Fi certified only to products that have successfully completed interoperability certification testing. The Wi-Fi Alliance was made up of over 800 companies from all over the globe as of 2017. Globally, more than 3.05 billion Wi Fi enabled devices are shipped each year.
Wi-Fi is a combination of several parts of IEEE 802 protocol and is intended to work seamlessly with Ethernet, its wired sibling. Wireless access points can be used to connect compatible devices to one another as well as to wired devices, and to the Internet. Different IEEE 802.11 protocols specify the Wi-Fi versions. The radio technologies determine the radio bands and maximum speeds. Wi-Fi uses the UHF radio bands 2.4 gigahertz, 120 mm (120 mm), and SHF radio bands 60 mm (60 mm). These bands can be subdivided into multiple channels. Although channels can be shared among networks, only one transmitter can transmit locally on any channel at any given moment.
Wi-Fi's wavebands are very absorbent and best for use in line-of-sight. Common obstructions like walls, pillars and home appliances can block Wi-Fi's wavebands. This can reduce range but also minimizes interference between networks in crowded areas. Access points (or hotspots) typically have a range of 20m (66 feet) indoors, while modern access points can claim a range up to 150m (490 feet) outdoors. Hotspot coverage may be limited to a single room, with walls that block radio waves or large areas with many access points. There is roaming allowed between them. The speed and spectral efficiency have improved over time. Some Wi-Fi versions can reach speeds of 9.6 Gbit/s (gigabit per sec) when used on compatible hardware.